Many systems are characterized by a source that transmits some status (e.g., sensor data, a list of neighboring nodes, social networking updates, a location, stock prices, etc.) to a monitor, where the objective is for the information observed at the monitor at any time be recently generated. A metric called the age of information or status age can be used to study the performance of such systems with the specific goal of characterizing the freshness of information at the monitor. The age at the time of observation can be defined as the amount of time elapsed from the generation of the status most recently received at the monitor to the current (observation) time.
Prior methods for controlling the age metric have several limitations. For example, choosing a queueing discipline to be last-come, first-served places the most recently generated packets in the front of the queue, giving them priority over older, more obsolete packets. A limitation of this approach is that all packets that enter in the queue are intended to be sent, regardless of how old they are. Thus, very stale information that is no longer useful can clog up the system (e.g., clogging up buffers and needlessly sending information that is no longer useful).
Features and advantages of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.